Connect Directly Via Ethernet
A Wi-Fi connection is fantastic when it comes to day-to-day internet traffic, but when it comes to VoIP, Wi-FI can lack the stability and bandwidth of an ethernet connection. Plugging into the internet is preferred for calling purposes.

VOIP Cable Router
Older routers cannot handle VOIP capabilities, so your company or remote employees must update to a more recent router. 

Buy Nice Cables
If you are using an ethernet to USB converter, stick to Apple or Microsoft adaptors. These may cost a bit more, but the bandwidth capacities are much higher. 

Use Business Fiber connection
Primarily for remote employees, business fiber connections have more quality internet with bigger bandwidth 25-50 Mbps per person.

Complete the Twilio Network Test

The most important thing to maintain effective call quality is a good solid reliable network. To ensure that your network fits the demands of VOIP calling, we recommend you complete the Twilio network test. 

The test verifies your company's network bandwidth. The bandwidth needs to sustain your office and your test result number range should be within 20 of the number of users on your team. If the range is too large, you need to configure the Quality of Service (QoS) to devote bandwidth to your calls.

To complete the Twilio network test, you will run a call test followed by a bandwidth test. Run the call test during a normal calling time where many reps are making calls. 

For the bandwidth test (or VoiceCall test), change your URL if you are in Europe. A region can be specified by adding it as a query param, eg. (regions for us1 portion)

  • au1 Australia 
  • br1 Brazil 
  • ie1 Ireland 
  • de1 Frankfurt 
  • jp1 Japan 
  • sg1 Singapore 
  • us1 United States 
  • gl1 Use Twilio's Global Low Latency routing to select the data center with the lowest-latency connection to your user. 

Finally, attempt the test when a computer is using wireless internet and when a computer is using wired/plugged into ethernet internet connection.

Set Up Network Infrastructure

In some cases, your network will need to be adjusted to allow the Dialer application to work. Any changes should be applied to all firewalls, routers, switches, load-balancers, and any other hardware or software that could block or manipulate network access to the destinations listed below.

If you are experiencing jitter or related issues that impact your voice quality, configure your router with QoS rules that prioritize UDP traffic on ports 10,000-20,000.

Things to Note:Due to the large range of UDP ports, consider all of your network traffic prior to setting up QoS. Follow the requirements listed below for more information or check out Twilio’s full list of Network Requirements.

Open up all phone Ports
Comply with the Twilio network activity requirements to make sure all ports are open so you may complete and receive calls on your network.

The SalesLoft Dialer uses the following ports (outbound):

  • TCP: 80, 443
  • UDP: 10,000 to 20,000

The ports listed above must be able to communicate to specific domains/IP addresses. Below are the Twilio domains and IP's you will need to allow access to.


Firewalls block outgoing traffic with media packets. By enabling a firewall, you allow a clear path for the domains and IP addresses that take top priority (in this case, Twilio domains and VOIP calls) within your network. 

Whitelist Twilio IPs
Twilio's requests come from different IP addresses, which can put your network on high alert, so we recommend that you validate the request that will come from Twilio. To do this your will need to whitelist Twilio's IPs and prioritize outbound media UDP ports ranging from 10,000 to 20,000.

Things to Note: Ensure both the SalesLoft and Twilio IP's / domains are excluded from stateful packet inspection (SPI), or you might experience high UDP/TCP connection times.

The IP's that we need to be whitelisted include the following: 


In some instances customers have advised that if a switch or other network hardware is plugged into an incorrectly configured Cisco Smart Switch it can override the whitelisting, to get around this I recommend that you do not plug any hardware other than hardware that is meant to be plugged into a smart switch, and ensure with your network team that it is configured to reflect the settings above.

Using DSCP
The Differentiated Services Code Point (aka DSCP) assigns, or tags, a forwarding behavior to the packets that travel through a network. DSCP tags in packets are useful for letting network appliances know how to prioritize traffic.

If congestion is an issue on your network, consider implementing DSCP on your network/domain. By default the SalesLoft Dialer traffic call gets a DSCP tag of 46. 

These details explain how DSCP will be implemented within your system: 

  • Twilio Client 1.3 enables DSCP by default in compatible browsers, like Google Chrome.
  • The SalesLoft Dialer works with the webRTC technology. Google Chrome will tag WebRTC media packets. This enables differentiated handling on a LAN, so that real-time media can be prioritized above other network traffic.
  • The Differentiated Services Field is located in the IPv4 header TOS octet or the IPv6 Traffic Class octet. A differentiated services-compliant network node (e.g. router) includes a classifier that selects packets based on the value of the DS field, along with buffer management and packet scheduling mechanisms capable of delivering the specific packet forwarding treatment indicated by the DS field value.
  • With Client 1.3 sent RTP packets will have a DiffServ codepoint on their local Wireshark packet captures. When we enable DSCP, the WebRTC engine marks the RTP packets with EF and below are the values related to Expedited forwarding.

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